“New York has become a safer city, and we have such richness of parks and culture that we're becoming a senior retirement destination,” said Linda I. Gibbs, New York's deputy mayor for health and human services. “They come not only with their minds and their bodies; they come with their pocketbooks.”

The round trip back to cities among empty nesters, rejoining those who simply grow old where they were once young, goes on, of course, across the country, and New York is not the only place trying to ease that passage. Cities like Cleveland and Portland, Ore., have taken steps to become more “age-friendly.” But perhaps never has a city as fast-paced and youth-oriented as New York taken on the challenge.

The Department of City Planning predicts that in 20 years, New York's shares of schoolchildren and older people will be about the same, 15 percent each, a sharp change from 1950, when schoolchildren outnumbered older residents by more than 2 to 1. By 2030, the number of New Yorkers age 65 and over — a result of the baby boomers, diminished fertility and increasing longevity — is expected to reach 1.35 million, up 44 percent from 2000.

Their economic power is significant. About a third of the nation's population is over 50, and they control half of the country's discretionary spending, according to a recent report by AARP , a group representing the interests of retirees. In some ways, the city has tackled the toughest challenges of making itself attractive to its older residents and those across the country who might consider retiring to the Upper East Side or Brooklyn Heights.

Crime has been in decline for close to two decades; the city has added more parkland than at any similar period in its history; and the 311 system has made dealing with the bureaucracy of government agencies and social services more manageable.

Now, the city is looking to enhance life here in more modest, but meaningful, ways. The New York Academy of Medicine adopted the idea of creating an age-friendly city from the World Health Organization in 2007, and went to the City Council and the Bloomberg administration for financial and political support. The academy has held more than 30 town hall meetings and focus groups with thousands of older people across the city. This summer, it is holding more intimate focus groups in East Harlem and on the Upper West Side.

What people say they want most of all is to live in a neighborly place where it is safe to cross the street and where the corner drugstore will give them a drink of water and let them use the bathroom. They ask for personal shoppers at Fairway to help them find the good deals on groceries. They want better street drainage, because it is hard to jump over puddles with walkers and wheelchairs.

“No bingo played here” could be Ms. Gibbs's motto. She is the conceptual artist behind the city's initiative, working with the Academy of Medicine. She is at the tail end of the boomer generation, having turned 51 on Sunday, her silvery bob a rebuke to fears of aging.

“The whole conversation around aging has, in my mind, gone from one which is kind of disease oriented and tragic, end- of-life oriented,” Ms. Gibbs said, to being “much more about the strength and the fidelity and the energy that an older population contributes to our city.”

One of her ideas is to hold a contest to design a “perch” to put in stores or on sidewalks where tired older residents doing errands could take a break. When boomers talk, she listens.

On Thursday, Dorian Block, a policy associate at the academy, held a focus group at the Carver Houses, a city housing project at 103rd Street and Madison Avenue in East Harlem. Sixteen people showed up. (Some meetings have drawn hundreds.)

They complained about broken elevators and litter, and some confessed to being lonely. They said that more stores should have public bathrooms. Now, said Dolores Marquez, 72, “I go to McDonald's and then I take a coffee because I have to go to the bathroom.”

The academy plans to incorporate the results of the focus groups into two pilot aging-improvement districts, one in East Harlem and the other on the Upper West Side, somewhat akin to business-improvement districts.

The exact details of how the districts will function are still being worked out, but the goal is to create a public-private partnership that would encourage businesses to voluntarily adopt amenities for the elderly. Examples could include window stickers that identify businesses as age-friendly; extra benches; adequate lighting; menus with large type; and even happy hour for older residents.

The new districts will be run by the academy, and eventually handed over to community groups and expanded to other neighborhoods, said Ruth Finkelstein, the academy's vice president for health policy. Some worry that what the Bloomberg administration is proposing is a menu of quick and dirty solutions for older residents while, in a tough economy, traditional services like senior centers and bus routes are being cut back.

“When we're talking about age-friendly, it should not only be the boomers who have retired from law firms, as opposed to the people who have worked all their lives and are now living in Brownsville,” said David Jones, president of the Community Service Society, which advocates for poor people and immigrants.

Fredda Vladeck, an expert at the United Hospital Fund in “naturally occurring retirement communities,” said she worried that the city would forget the frail older people. Ms. Gibbs said the point was to build on what is already there, and to make life better for everyone.

The city enlisted students at New York University's Wagner Graduate School of Public Service to develop a walking survey that, if adopted, will rate the city's age-friendliness by standards like the frequency of cracked sidewalks and hospitals.

Slowing the pace of life is tough in New York, where every red light is viewed as a challenge. But the city is trying. While most adults average four feet per second when crossing the street, older residents manage only three, transportation experts say. So signals have been retimed at intersections like Broadway and 72nd Street, where pedestrians now have 29 seconds to cross, four more than before.

Even senior centers are being redefined as places with artists in residence, like Judy Hugentobler, a sculptor from Staten Island. Ms. Hugentobler is teaching art classes at the Educational Alliance's Sirovich Senior Center, on East 12th Street, in exchange for being able to use the kilns, clay and glazes in her projects.

“Senior centers are great, but they have a stigma whether you like it or not,” said Councilwoman Gale A. Brewer of the Upper West Side. “It's just not for everybody. But what is for everybody is a bench. What is for everybody is discounts at the grocery store when you're over 65.”